You may be able to handle short videos. But that i5 processor will likely struggle with longer 4K videos. Though it's worth a try. Can someone provide you with same sample video from that GoPro?

Meantime, before you even attempt to edit the video, open a sample in the free download MediaInfo. Set MediaInfo's View menu to Text and make sure you do not see the words "Variable Frame Rate" in the report. Variable Frame Rate is a compression system that can make for smaller files -- but it can also challenge Premiere Elements and most other video editing programs.

Also be aware that with the Hero 6 GoPro is now using the HEVC format. Make sure your editor can support HEVC format.

High Efficiency Video Coding (HEVC) – also known as H.265 – is a video compression standard that allows GoPro to capture large video content, such as 4K60 and 1080p240, at roughly half the file size with equivalent image quality. Adoption for this new standard is increasing, and is natively supported on Android™ 5.0+ and iOS™ 11 on newer phones and tablets with more powerful processors. Moreover, HEVC is natively supported on Windows® 10 and MacOS® High Sierra on newer desktop computers with more powerful processors.

Sidd

“Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”Albert Einstein

I though that Vegas was able to create proxy files for those 4k files so that you can edit with those smaller files then when you render it uses the original files. Just as suggestion. Maybe you could try a trial copy of Vegas to see it that works better than your program.